The conceptual thrust of this proposal is to develop a method for generalizing the design of engineering control of workplace hazards. In particular we propose to develop emission factors, based on field observations, for four types of commonly encountered, hazardous, open tank processes: degreasing (both vapor and cold cleaning processes) ; electroplating (chrome and nickel plating); offset printing; and wave soldering. The value of the emission factor approach is that the effect of the particular interior space in which the data are collected is removed. The factors will be developed from the area concentration pattern surrounding each device while production is taking place, using mathematical models describing a mass balance on the contaminant to transform this pattern for a particular source to an emission rate. To systematically describe the variability of emissions, the factors will be related to source activity, process conditions and equipment geometry. A total of 12 source tests will be carried out consisting of 12 1-hour sampling periods which will also include measurements of general and local exhaust ventilation. The results of this study will provide: A compilation of activity-based emission factors for Cr and Ni electroplating, vapor degreasing and cold cleaning, wave soldering, and offset printing; A measure of the variability in emissions which can be expected from such processes; Actual determinations, based on an emission mass balance, of control device performance for each of the processes studied; A generalized basis for estimating workplace concentrations from these types of sources; And a mass-balance basis for evaluating control design alternatives.